High-Field FMR of Cu/CoFe Films and the Effects of N and Ti Constituents on the Anisotropy Stability in FeXN Films

We have recently been able to obtain FMR data from Cu/CoFe using a 94 GHz FMR spectrometer with magnetic fields up to six tesla. Two spectra from these films taken at a field near 5.5 T are shown below. These measurements allow us to observe spectra when the external field is perpendicular to the film plane, and when the film is rotated out of the film plane. Spectra taken in the perpendicular orientation include absorption lines from spin waves, allowing us to determine the exchange coupling constant, A, and rotation data gives precise values for the perpendicular anisotropy and gyromagnetic coupling constant.

Studies of multilayer films of FeTiN and Fe, Ti, and FeN, before and after annealing are providing information about the role of Ti and N constituents in the magnetic and structural properties of FeXN materials. The studies include XRD and XPS measurements of the structural changes in the films, and the atomic percentages of the constituents as a function of Ti and N content before and after annealing. These studies are providing valuable information to help explain the unusual results of thermal effects on the anisotropy found in these materials.